Question

If square of a number ends with 5,then its cube ends with 25 . Is the statement correct ?

Answer 1

If n^2 ends with 5, then n is a multiple of 5. (why?)
Thus, n = 10k+5
So, n^3 = 1000k^3 + 1500k^2 + 750k + 125
Looks like It will end in either 25 (even k) or 75 (odd k).
Check:
15^3 = 3375
25^3 = 15625

Answer 2

Thank you sir.